Currency in the form of coins was
introduced into Egypt during the Late Period, but for most of Ancient Egyptian
history a barter-exchange system based on the value of various weights of
silver or copper was used. Goods were valued in terms of how much copper
or silver would be required to buy them, and then exchanged for other
goods with the same value in metal. For example, an Ostracon from Deir el
Medina, #73, verso, described by Jac Jansen in Commodity Prices from the
Ramesside Period (Leiden, 1975) gives an example of a coffin worth 25.5 deben of copper, which was purchased for
two goats, one pig, two sycamore logs, and 13.5 deben of actual copper. There are many such exchanges
recorded from Ancient Egypt. Units of grain and oils were also used in exchange-barter.
As in modern economies, rates of exchange varied with supply. The weight,
in grams, of a deben changed from the
Old and New Kingdoms to the Late Period, but a qedet, (also known as a kite)was always valued at one tenth of a deben. Stone and bronze weights equivalent to specific amounts of copper were
used in everyday market transactions, and could be checked against more
official weights kept in temples.

In addition to the ordinary system
of deben and quedet, the Egyptians
used measuring systems borrowed from their neighbours in Mesopotamia, Syria and
the Aegena. These were introduced by traders, merchants, and by
soldiers.

This lentoid hematite weight has not yet been identified with any of the known
systems.This is not unusual for metal
weights, however.As Flinders Petrie,
who excavated many weights at Naukratis cautioned, “Metal weights have almost
always undergone alteration over the centuries, both losing and gaining weight.
The loss is by wear, by solution of compounds, and, especially on bronze
weights, by scaling of compounds; the gain is by the oxygen and carbonic acid
locked up in the compounds, for nearly half the weight of green carbonate of
copper is gain from the air.” Glass
Stamps and Weights, British School of Archaeology, 1926, p.22.